Tiiaddeus norris



(No Model.)

T. NORRIS.

MARKER FOR SLIDE RULES.

No. 540,184. Patented May 28, 1895.

m: cams PETERS c0, PHoToumc v WASMINGYON,

UNITED STATES PATENT OFFICE.

TI-IADDEUS NORRIS, OF YVASHINGTON, DISTRICT OF COLUMBIA.

MARKER FOR SLIDE-RULES.

SPECIFICATION forming part of Letters Patent No. 540,184, dated May 28,l. 895. Application filed October 24, 1894. Serial No. 526,880. (1V0model.)

To all whom it may concern:

Be it known that I, THADDEUS NORRIS, of Vashington, in theDistrict ofColumbia, have invented certain new and useful Improvements inSlide-Rules; and I dohereby declare the following to be a full, clear,and exact description of the invention,such as will enable othersskilled in the art to which it appertains to make and use the same.

This invention contemplates certain new and useful improvements in sliderules and relates particularly to those composed of two or moreconcentrically arranged disks pivoted together, but certain features ofthe improvements are, however, applicable to rules havinglongitudinally-movable members; also rules having verniers, and, infact, can be used with allscales of graduation.

The objects of the invention are, first, to provide an improved simpleand inexpensive marker or runner by which the scales or marks ofgraduation can be quickly and easily read, and, second, to enable theupper one of two movable concentric disks to be readily and easilygrasped and turned independently of the lower disk. The first object Iaccomplish by securing direct to the marker or runner a semi orpartially cylindrical lens which magnifies transversely, that is, thespaces between the division lines on the scale are magnified as are alsothe widths of such division lines, while the lengths of the latter arenot perceptibly elongated. The lens is carried by the marker so as to bealmost in direct contact with the rule. The second object is effected bypro viding the lower disk with one or more elongated openings to permitthe upper or smaller disk to be grasped between the thumb and finger inorder to turn it independently of the other disk thus permitting bothdisks to be manipulated by the fingers of one hand of the operator.

The invention will be hereinafter fully set forth and particularlypointed out in the claims.

In the accompanying drawings, Figure l is a plan view showing a portionof a circular slide-rule with my improved runner. Fig. 2 is a side view,parts being broken away. Fig. 3 is a transverse sectional view on theline 3 3, Fig. 1. Fig. 4 is a similar View of a slight modification.Fig. 5 is a plan view of a second modification, parts being broken away.Fig. 6 is a transverse sectional view on the line 6 6, Fig. 5.

Referring to the drawings, A and A designate two disks pivotallyconnected together at their centers by a headed rivet a. Upon thesedisks are circularly-arranged series of scales or divisional-lines whichmay be of any preferred plan or method and hence further referencethereto is not necessary. The under disk A is of greater diameter thanthe upper disk, and it is provided with one or more, preferably three,openings at, which are elongated or curved concentrically with the upperdisk. These openings allow the upper disk to be grasped between thethumb and finger, one touching the upper and the other the under side ofsaid upper disk, whereby the latter can be turned to bring it inposition for performing diiferent calculations without moving the lowerdisk both disks being manipulated by the fingers of the hand of theoperator in which the two disks are held.

B is the marker or runner, which comprises an approximately rectangularframe 17 piv oted at its inner end by rivet CL and having at its outerend two inwardly bent fingers l) which hug or overlap the periphery ofthe disk A and serve as guides for the marker or runner. A lip ortongue 1) projects from the outer end of this frame. The runner can bereadily turned by grasping this lip or tongue. A longitudinal slot oropening b is formedin the frame the same extending to within a shortdistance of each end thereof. From the parallel side-bars of this frameproject opposite lips or flanges b 0 is a lens of semi or partiallycylindrical form in cross-section, that is, it is convex on its upperside and fiat on its under side. This lens is fitted in frame Z) withits fiat side down. It extends entirely over the slot in said frame andis held in place by the lips or flanges which are bent inwardly againstthe opposite sides thereof. At its inner end this lens fits against twoshort lugs d which limit its inward movement. Extending longitudinallybeneath the lens, from one end of the slot 19 to the other, is astraight line at, which serves as a guide and may consist of a wire orhair secured at its ends to perforated portions of the frame, or in lieuthereof, a groove or scratch (1 may be formed in the under or flat usedin connection with a Vernier and scale this guide-line is not necessaryand hence may be omitted.

In Fig. 5 I have shown my improved marker" or runner applied to anordinary straight slide-rule D. The frame B is made oblong and has acentral opening 01 and two endslots d Over these slots are two lenses Eand E. The division-lines at the extreme ends of the rule are to be readthrough the outer lens E, while those in the center can be read througheither lens. The sides of the runner may be bent or curved to overhangthe grooved edges of the rule which serve'as guides therefor. This formof marker or runner is for the purpose of securing a long bearing inorder that the lens and the guide-line thereunder may remain perfectlyperpendicular or at right angles to the rule'when reading from scales atits extreme ends.

The advantages of my invention are apparent to those skilled in the artand it will be specially observed that by providing a marker or runnerwith a semi or partially cylindrical lens the division-lines'andintermediate spaces are magnified transversely and but little if anylongitudinally. Hence by attaching this lens directly to the-marker thereading of a scale'can be quickly and easily accomplished and by makingthe lower disk with curved openings the upper disk can be easily turnedwithout moving the former. It will be understood, of course, that I'donot restrict myself to the use-of my improved marker or runner inconnection with slide rules of the character herein specified, as it maybe employed to like advantage in reading scales on surveying,astronomical, and other instruments. I claim as my invention 1. A markeror runner for graduated scales and the like having a slot or openingtherein, a lens corresponding to but slightly larger than said slot oropening secured over the latter, said lens being of semi-cylindricalform and having a flat side provided with a central longitudinal grooveforming a guide-line, substantially as set forth.

2. The herein-described improved sliderule consisting of the two diskspivotally connected together at their centers, one of said disks beingof greater diameter than the other and provided with a series ofcircularly arranged disconnected finger-slots, the marker or runnerpivoted at its inner end to the center of said disks and having itsouter end provided with fingers for overlapping the periphery of saidlarger disk, said marker or runner having a longitudinal openingtherein, and a semi-cylindrical lens fitted directly over saidlongitudinal opening and having a a lower flat side provided with agrooveor recess, substantially as set forth.

3. The herein-described improved slide rule composed of two diskspivotally connected together, one of said disks being of greaterdiameter than the other and having a series of circularly arrangeddisconnected finger slots, a marker or runner pivoted at its inner endto the center of said disks and having its outer end overlapping theperiphcry of said large disk, said marker or runner having alongitudinal opening therein, a semicylindrical lens fitted over saidopening and having a lower fiat side, and a guide-line extendinglongitudinally beneath said lens from end to endthereof, substantiallyas set forth.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

THADDEUS NORRIS.

Witnesses:

J. NOTA MoGILL, WM. S. HODGES.

